The present invention relates to a device for electrical measurement and/or calibration of a test: head of a testing device for testing electronic components.
Complex electronic components, such as microprocessors, may be tested and/or measured in regard to their proper functioning and performance with the aid of special testing devices. For this purpose, a testing device of this type has a test head, which has multiple electronic contacts arranged in a contact region, which is, in particular, flat. The components to be tested are positioned on a circuit board which has contact zones connected to the terminals of the components to be tested. As the circuit board is placed on the test head, the contacts of the test head may contact the contact zones of the circuit board, so that the test routine may run.
For example the product lines 83000 and 93000 from Agilent Technologies, as disclosed e.g. under http://www.ate.agilent.com/ste/products/intelligent test/SOC test/SOC Tec h Oview.shtml, represent these types of testing devices. Further testing devices are described in, for example, European Patent Application 1092983, European Patent Application 999450, European Patent Application 965845, European Patent Application 859318, European Patent Application 864977, European Patent Application 886214, European Patent Application 882991, U.S. Pat. No. 5,499,248, and U.S. Pat. No. 5,453,995.
In order to be able to ensure high quality for the tests of the testing device, it is essential to calibrate the test head electrically or electronically as precisely as possible. The measurement and/or calibration of the test head is performed with the aid of a device of the type initially described, a signal transmission having to be implemented on the more than, for example, 1000 contacts of the test head.
It is an object of the present invention to provide an embodiment for a device of the type initially described which improves the measurement and/or calibration of the test head. This object is achieved by the object of the independent claim. Advantageous embodiments are objects of the dependent claims.
The present invention is based on the idea of equipping the device with a contact head which has one or more measurement contacts for contacting the contacts of the test head and which may, using a positioning unit, automatically approach and contact all contacts necessary for measuring and/or calibrating the test head. In other words, the device is implemented in such a way that its contact head automatically approaches and contacts all contacts necessary for measuring and/or calibrating the test head, so that the device may perform the necessary measurements and/or calibration procedures automatically. The calibration of a test head equipped with a large number of contacts may, for example, last several hours, no interaction of operating personnel typically being necessary during this time; the advantage is obvious.
The device according to the present invention includes a contacting unit which comprises the contact head, including the positioning unit. According to a particularly advantageous embodiment, the control unit is housed in a base unit and the contacting unit may be implemented so it is removable from the base unit, the contacting unit being connected to the base unit via a flexible cable arrangement. In order to dock the contacting unit on the test head, the contacting unit may be removed from the base unit, which simplifies the handling of the device. This is because the contacting unit only comprises the components necessary for the automatic contacting of the contacts of the, test head, while the base unit comprises the components necessary for the actual measurements and calibration procedures, such as the computer, control units, power supply unit, and the like. In particular, power is supplied to the contacting unit via a cable arrangement, originating from the base unit.
In a refinement, the contacting unit may be implemented in such a way that it may be set down on the base unit with its docking side, which is attachable to the test head, upward and may also be set down on the base unit with its docking side downward. Through this construction, the spectrum of application of the device may be elevated. When the docking side points upward, the device may be moved under the test head, so that the test head may be set down on the contacting unit with its contact region pointing downward. When the docking side points downward, it is protected, so that damage, particularly fouling of the components of the contacting unit, may be avoided.
For the measurement and calibration of the test head, signal transmissions must be implemented on a large number, particularly on all, of the contacts of the test headxe2x80x94as described above. The measurement and/or calibration procedures typically include multiple individual measurements in this case, for each of which there must only be signal transmission at a comparatively small number of contacts, for example two. To perform the measurement and/or calibration of the test head, it is possible in principle to contact any desired number of contacts simultaneously. The individual measurements are then performed, for example, in that, with the aid of an appropriate relay matrix, the small number of contacts necessary for the respective individual measurement are activated, while all other contacts, which are not necessary for this individual measurement, are deactivated. According to a preferred embodiment of the present invention, the contact head has exactly enough measurement contacts so that in each case only the contacts of the test head necessary for the respective individual measurement are contacted. In this embodiment, electronic activation and deactivation of specific contacts, e.g., using a relay matrix, may be dispensed with. The signal transmission may therefore be performed directly, i.e., not via a selection circuit or relay matrix, and the quality of the transmittable signals, and therefore the quality of the measurements and the achievable calibration, may be improved.